Oxygenator with thermal insulation

ABSTRACT

An oxygenator includes a housing having a blood inlet and a blood outlet, the blood inlet extending into an interior of the housing. A heat exchanger is disposed within the housing, and is coupled, at an inlet end, to a heat-exchange fluid inlet. A gas exchanger also is disposed within the housing, and includes a bundle of gas-exchange fibers coupled, at a gas outlet end, to a gas-exchange fluid outlet. The oxygenator includes at least one insulator configured to thermally insulate at least the gas outlet end of the bundle of gas-exchange fibers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/612,211, filed Nov. 8, 2019, which is a national stage entry ofApplication Serial No. PCT/IB17/53229, filed Jun. 1, 2017, thedisclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to medical devices and methods forprocessing blood in extracorporeal circulation. More specifically, thedisclosure relates to oxygenators.

BACKGROUND

Blood perfusion entails encouraging blood through the vessels of thebody. For such purposes, blood perfusion systems typically entail theuse of one or more pumps in an extracorporeal circuit that isinterconnected with the vascular system of a patient. Cardiopulmonarybypass surgery typically requires a perfusion system that provides forthe temporary cessation of the heart to create a still operating fieldby replacing the function of the heart and lungs. Such isolation allowsfor the surgical correction of vascular stenosis, valvular disorders,and congenital heart defects. In perfusion systems used forcardiopulmonary bypass surgery, an extracorporeal blood circuit isestablished that includes at least one pump and an oxygenation device toreplace the functions of the heart and lungs.

More specifically, in cardiopulmonary bypass procedures oxygen-poorblood, i.e., venous blood, is gravity-drained or vacuum suctioned from alarge vein entering the heart or other veins in the body (e.g., femoral)and is transferred through a venous line in the extracorporeal circuit.The venous blood is pumped to an oxygenator that provides for oxygentransfer to the blood. Oxygen may be introduced into the blood bytransfer across a membrane or, less frequently, by bubbling oxygenthrough the blood. Concurrently, carbon dioxide is removed across themembrane. The oxygenated blood is filtered and then returned through anarterial line to the aorta, femoral artery, or other artery.

During the use of any oxygenator, vapor condensation may occur withinthe gas-exchange fibers of the oxygenator. When this occurs, it may beevidenced by a progressive decrease of gas exchange performances.Conventionally, in order to recover normal functionality, theperfusionist manually removes the condensed water from the gasexchanger. This is not often easy to do. Therefore, it is desirable toreduce and/or prevent vapor condensation.

SUMMARY

Embodiments of the subject matter disclosed herein include an oxygenatorcomprising a housing having a blood inlet and a blood outlet, the bloodinlet extending into an interior of the housing; a heat exchangerdisposed within the housing, the heat exchanger coupled, at an inlet endto a heat-exchange fluid inlet; a gas exchanger disposed within thehousing, the gas exchanger comprising a bundle of gas-exchange fiberscoupled, at a gas outlet end, to a gas-exchange fluid outlet; and atleast one insulator configured to thermally insulate at least the gasoutlet end of the bundle of gas-exchange fibers. In embodiments, the atleast one insulator comprises an insulating material and/or aninsulating chamber. In embodiments, the at least one insulator includesan insulating material, wherein the insulating material is transparent(e.g., a transparent paint, coating, adhesive tape, etc.). Inembodiments, the at least one insulator includes an insulating chamber,wherein the insulating chamber is configured to receive an insulatingfluid. The insulating fluid may comprise a portion of a flow ofheat-exchange fluid being provided to the oxygenator. In embodiments, aconduit is disposed outside of the oxygenator housing and configured toprovide the insulating fluid to the insulating chamber. In embodiments,the insulating chamber surrounds at least a portion of the housing.

In embodiments, the oxygenator includes a first end cap disposed at afirst end of the housing, and a second end cap disposed at a second endof the housing, wherein the insulating chamber is partially definedbetween an outer surface of the second end of the housing and an innersurface of the second end cap. In embodiments, the insulating chamber isat least partially defined by a channel defined in an inner surface ofthe second end cap. In embodiments, the oxygenator further includes aconnecting channel defined in the inner surface of the second end cap,the connecting channel extending between a heat-exchange fluid inletchannel and the insulating chamber. In embodiments, the oxygenatorfurther includes an additional connecting channel defined in the innersurface of the second end cap, the additional connecting channelextending between the insulating chamber and a heat-exchange fluidoutlet channel. The connecting channel and additional connecting channelmay be offset from one another.

Embodiments of the subject matter disclosed herein include an oxygenatorcomprising a housing having a blood inlet and a blood outlet, the bloodinlet extending into an interior of the housing; a heat exchangerdisposed within the housing, the heat exchanger coupled, at an inlet endto a heat-exchange fluid inlet; a gas exchanger disposed within thehousing, the gas exchanger coupled, at a gas outlet end, to agas-exchange fluid outlet; and an insulating chamber configured toreceive an insulating fluid to thermally insulate at least the gasoutlet end of the bundle of gas-exchange fibers. According toembodiments, the oxygenator includes an insulating material disposed onan outer surface of the housing (e.g., a transparent paint, coating,adhesive tape, etc.). In embodiments, the insulating chamber surroundsat least a portion of the housing. In embodiments, the oxygenatorfurther includes a first end cap disposed at a first end of the housing,and a second end cap disposed at a second end of the housing, whereinthe insulating chamber is bounded by an outer surface of the second endof the housing, an inner surface of a flange extending from the housing,and an inner surface of the second end cap. In embodiments, theinsulating chamber comprises an at least partially annular chamberextending at least partially around the gas outlet end of the gasexchanger. In embodiments, the insulating fluid comprises a portion of aflow of heat-exchange fluid being provided to the oxygenator.

Embodiments of the subject matter disclosed herein include an oxygenatorcomprising a housing having a blood inlet and a blood outlet, the bloodinlet extending into an interior of the housing; a first end capdisposed at a first end of the housing; a second end cap disposed at asecond end of the housing, wherein the insulating chamber is partiallydefined between an outer surface of the second end of the housing and aninner surface of the second end cap; a heat exchanger disposed withinthe housing, the heat exchanger coupled, at an inlet end, to aheat-exchange fluid inlet; a gas exchanger disposed within the housing,the gas exchanger comprising a bundle of gas-exchange fibers coupled, ata gas outlet end, to a gas-exchange fluid outlet; and an insulatingchamber configured to receive an insulating fluid to thermallynsulate atleast the gas outlet end of the bundle of gas-exchange fibers, whereinthe insulating chamber is at least partially defined by a channeldefined in an inner surface of the second end cap.

While multiple embodiments are disclosed, still other embodiments of thepresent disclosure will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the disclosed subject matter. Accordingly,the drawings and detailed description are to be regarded as illustrativein nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative oxygenator, inaccordance with embodiments of the disclosed subject matter.

FIG. 2 is a partial cross-sectional side view of an illustrativeoxygenator, taken along line B-B depicted in FIG. 3 , in accordance withembodiments of the disclosed subject matter.

FIG. 3 is a cross-sectional view of an end cap of the illustrativeoxygenator depicted in FIG. 2 , in accordance with embodiments of thedisclosed subject matter.

FIG. 4 is another partial cross-sectional side view of the illustrativeoxygenator depicted in FIGS. 2 and 3 , taken along line A-A depicted inFIG. 3 , in accordance with embodiments of the disclosed subject matter.

FIG. 5 is a schematic diagram of an illustrative oxygenator, inaccordance with embodiments of the disclosed subject matter.

While the disclosed subject matter is amenable to various modificationsand alternative forms, specific embodiments have been shown by way ofexample in the drawings and are described in detail below. Theintention, however, is not to limit the disclosure to the particularembodiments described. On the contrary, the disclosure is intended tocover all modifications, equivalents, and alternatives falling withinthe scope of the disclosure as defined by the appended claims.

As the terms are used herein with respect to measurements (e.g.,dimensions, characteristics, attributes, components, etc.), and rangesthereof, of tangible things (e.g., products, inventory, etc.) and/orintangible things (e.g., data, electronic representations of currency,accounts, information, portions of things (e.g., percentages,fractions), calculations, data models, dynamic system models,algorithms, parameters, etc.), “about” and “approximately” may be used,interchangeably, to refer to a measurement that includes the statedmeasurement and that also includes any measurements that are reasonablyclose to the stated measurement, but that may differ by a reasonablysmall amount such as will be understood, and readily ascertained, byindividuals having ordinary skill in the relevant arts to beattributable to measurement error; differences in measurement and/ormanufacturing equipment calibration; human error in reading and/orsetting measurements; adjustments made to optimize performance and/orstructural parameters in view of other measurements (e.g., measurementsassociated with other things); particular implementation scenarios;imprecise adjustment and/or manipulation of things, settings, and/ormeasurements by a person, a computing device, and/or a machine; systemtolerances; control loops; machine-learning; foreseeable variations(e.g., statistically insignificant variations, chaotic variations,system and/or model instabilities, etc.); preferences; and/or the like.

Although the term “block” may be used herein to connote differentelements illustratively employed, the term should not be interpreted asimplying any requirement of, or particular order among or between,various blocks disclosed herein. Similarly, although illustrativemethods may be represented by one or more drawings (e.g., flow diagrams,communication flows, etc.), the drawings should not be interpreted asimplying any requirement of, or particular order among or between,various steps disclosed herein. However, certain embodiments may requirecertain steps and/or certain orders between certain steps, as may beexplicitly described herein and/or as may be understood from the natureof the steps themselves (e.g., the performance of some steps may dependon the outcome of a previous step). Additionally, a “set,” “subset,” or“group” of items (e.g., inputs, algorithms, data values, etc.) mayinclude one or more items, and, similarly, a subset or subgroup of itemsmay include one or more items. A “plurality” means more than one.

DETAILED DESCRIPTION

In hollow fiber oxygenators, blood is circulated outside the fibers,while gas flows inside. Gas temperature within most of the oxy hollowfiber bundle is virtually homogeneous and tends to be similar to that ofthe blood temperature, which in turn tends to be similar to theheat-exchange fluid temperature. Therefore, within most of the oxybundle, water vapor contained in gas and extracted with CO2 from bloodthrough fiber microporosity is not likely to condense, as there isgenerally is virtually no difference in temperature between gas andblood. However, gas temperature often significantly decreases towardsthe gas outlet end of the gas exchanger, where the fibers come intocontact with a potting volume (at temperature lower than gas), whichacts like a cooling element and causes water vapor condensation insidethe fibers.

Embodiments of the subject matter disclosed herein facilitate reducingthis temperature difference and, in turn, reducing the occurrence ofcondensation within the gas-exchange fibers. In embodiments, aninsulator is disposed adjacent the gas outlet end of the gas exchanger.The insulator may include an insulating chamber that is disposedadjacent the gas outlet end of the gas exchanger (and, in some cases, atleast a portion of the oxygenator housing), and is configured to receivean insulating fluid, which may, in embodiments, be a portion of aheat-exchange fluid flow. In embodiments, the insulator may include aninsulating material that may be applied to an external surface of theoxygenator housing. Embodiments may include both an insulating chamberand an insulating material.

The disclosure pertains to a blood processing apparatus that, accordingto various embodiments, includes a gas exchanger (also commonly referredto as an oxygenator) and, in embodiments, also a heat exchanger. Inembodiments, the term “oxygenator” may be used to refer to a bloodprocessing apparatus configured to perform a gas exchange process suchas, for example, a stand-alone gas exchanger or an integrated structurethat combines a gas exchanger with another system (e.g., a heatexchanger) in a unitary device. In embodiments, for example, a heatexchanger and a gas exchanger are disposed in a concentric fashion withone component located inside of the other component. According to otherembodiments, the heat exchanger and gas exchanger are structurallydistinct structures operable coupled to each other. In embodiments, anoxygenator may be used in an extracorporeal blood circuit. Anextracorporeal blood circuit, such as may be used in a bypass procedure,may include several different elements such as a heart-lung machine, ablood reservoir, as well as an oxygenator. Oxygenators may also be usedin procedures such as extracorporeal membrane oxygenation (ECMO), and/orthe like.

FIG. 1 is a schematic illustration of an oxygenator 100. The oxygenator100 may include a gas exchanger and, in embodiments, a heat exchanger.In embodiments, the oxygenator 100 may include any number of otherdevices such as, for example, a blood filter, a blood pump, and/or thelike. According to embodiments, a heat exchanger and a gas exchanger maybe integrated within the oxygenator 100. The oxygenator 100 includes ahousing 102, a first end cap 104 that is secured to a first end 106 ofthe housing 102 and a second end cap 108 that is secured to a second end110 the housing 102. In embodiments, the first end cap 104 and/or thesecond end cap 108 may be adhesively secured in place. In embodiments,the first end cap 104 and/or the second end cap 108 may be snap-fittedinto place, threaded onto their respective ends of the housing 102,and/or the like.

In embodiments, the housing 102 may include structures that enableattachment of the housing 102 to other devices. While the housing 102 isillustrated as generally cylindrical in shape, in embodiments, thehousing 102 may have any number of different shapes (e.g. rectangular orother parallelogram cross-sectional shapes, oblong cross-sectionalshapes, etc.). In embodiments in which the oxygenator 100 includes aheat exchanger and a gas exchanger, each of the heat exchanger and thegas exchanger may have approximately the same cross-sectional shape oreach may have a different cross-sectional shape. In embodiments, theheat exchanger may be inside the gas exchanger. In embodiments, the heatexchanger and the gas exchanger may be concentric.

In embodiments, a blood inlet 112 extends into the housing 102 and ablood outlet 114 exits the housing 102. The illustrated oxygenator 100includes a gas-exchange fluid inlet 116 configured to facilitateproviding a gas-exchange fluid (such as air, oxygen, a mixture of oxygenand other gases, and/or the like) to the oxygenator 100, a gas-exchangefluid outlet 118 configured to facilitate removing a gas-exchange fluidfrom the oxygenator 100, a heat-exchange fluid inlet 120 configured tofacilitate providing a heat-exchange fluid such as water to theoxygenator 100, and a heat-exchange fluid outlet 122 configured tofacilitate removing a heat-exchange fluid from the oxygenator 100 and,for example, that, in the illustrated embodiment, is behind theheat-exchange fluid inlet 120. In embodiments, the heat-exchange fluidinlet 120 may be disposed at one end of the housing 102 while theheat-exchange fluid outlet 122 may be disposed at an opposite end of thehousing 102. The heat-exchange fluid inlet 120 is configured tofacilitate providing heat-exchange fluid to a heat exchanger disposedwithin the housing 102. Additionally, in embodiments, the heat-exchangefluid inlet 120 may be configured to facilitate providing heat-exchangefluid to an insulating chamber 124 disposed adjacent a gas-exchangefluid outlet region to facilitate reducing a temperature gradientbetween blood and gas exiting the oxygenator 100. In embodiments, theoxygenator 100 may include a separate heat-exchange fluid inlet coupledto the insulating chamber 124. In embodiments, the oxygenator 100 mayinclude a conduit disposed outside or inside the housing 102 thatfacilitates transporting a portion of the heat-exchange fluid from theheat exchanger to the insulating chamber 124 and/or from the insulatingchamber 124 to the heat exchanger. In this manner, embodiments of thesubject matter disclosed herein may be configured to facilitatereduction of condensation within the gas exchanger.

In embodiments, the blood inlet 112 and/or the gas-exchange fluid inlet116 may be integrally formed with the first end cap 104. For example, insome cases, the first end cap 104 may be injection molded with the bloodinlet 112 and/or the gas-exchange fluid inlet 116 formed as part of theinjection molded part. In embodiments, the first end cap 104 may beformed having apertures to which the blood inlet 112 and/or thegas-exchange fluid inlet 116 may be coupled. Similarly, in embodiments,the heat-exchange fluid inlet 120 and/or the heat-exchange fluid outlet122 may be integrally formed with the second end cap 108. For example,in some cases, the second end cap 108 may be injection molded with theheat-exchange fluid inlet 120 and/or the heat-exchange fluid outlet 122formed as part of the injection molded part. Similarly, in embodiments,the second end cap 108 may be injection molded with the gas-exchangefluid outlet 118 formed as part of the injection-molded part. Inembodiments, the second end cap 108 may be formed having apertures towhich one or more of the heat-exchange fluid inlet 120, theheat-exchange fluid outlet 122 and/or the gas-exchange fluid outlet 118may be coupled. In embodiments, one of the heat-exchange fluid inlet 120and the heat-exchange fluid outlet 122 may be located in the first endcap 104 while the other of the heat-exchange fluid inlet 120 and theheat-exchange fluid outlet 122 may be located in the second end cap 108.In embodiments, the heat-exchange fluid inlet 120 and outlet 122 may belocated in the first end cap 104, while in other embodiments, theheat-exchange fluid inlet 120 and outlet 122 may be located in thesecond end cap 108.

In embodiments, the oxygenator may include a purge port 126 that may beused for purging air bubbles from the interior of the oxygenator. Thepurge port 126 may be configured to permit gases (e.g., air bubbles)mixed with the exiting blood to be vented or aspirated and removed fromthe oxygenator 100. The positions, with respect to the housing 102 ofthe inlets, outlets and purge port are merely illustrative, as otherarrangements and configurations are contemplated.

According to embodiments, the oxygenator 100 may include an insulatingmaterial disposed on the housing 102 configured to reduce heatdispersion from the oxygenator 100 to the environment. The insulatingmaterial may be employed in lieu of, or in addition to, an insulatingchamber. The term “insulator” may refer to insulating material and/or aninsulating chamber. According to embodiments, any number of differenttypes of insulating materials may be provided on, or in, the housing102, and, in embodiments, a number of insulating materials may be usedsimultaneously. In embodiments, the insulating materials may include,for example, transparent (or at least partially transparent) coatings orpaints with low thermal conductivity such as, for example, BASF Top Coat603 Full White, Clear Coat Tixo Opaque 10 Gloss GP31-0436, and/or thelike.

In embodiments, the insulating material may be removeably or permanentlyfixed to an outer surface of the housing 102 and/or an inner surface ofthe housing 102. For example, in embodiments, the insulating materialmay include one or more blankets wrapped around at least a portion ofthe housing 102. The blanket(s) may be secured in place by folding,tying, or otherwise manipulating the blanket; using an adhesive; using amechanical fastener (e.g., a snap, clip, etc.); and/or the like. Inembodiments, insulating blankets may be made of neoprene, aluminum foil,and/or the like. According to embodiments, the insulating material maybe an insulating adhesive such as, for example, an insulating tape 128that is wrapped around at least a portion of the outer surface of thehousing. For example, a strip of insulating tape 128 may be wrappedaround the end of the housing 102 adjacent a gas outlet end of thebundle of gas-exchange fibers. By applying an insulating material to theoxygenator housing 102, heat dispersion from the device to theenvironment may be reduced, thus decreasing the blood/gas temperaturegradient and, in turn, inhibiting condensation within the gas-exchangefibers.

The illustrative oxygenator 100 shown in FIG. 1 is not intended tosuggest any limitation as to the scope of use or functionality ofembodiments of the present disclosure. The illustrative oxygenator 100should not be interpreted as having any dependency or requirementrelated to any single component or combination of components illustratedtherein. Additionally, various components depicted in FIG. 1 may be, inembodiments, integrated with various ones of the other componentsdepicted therein (and/or components not illustrated), all of which areconsidered to be within the ambit of the present disclosure.

FIGS. 2-4 depict an illustrative oxygenator 200 having athermally-insulating chamber, according to embodiments of the disclosedsubject matter. FIG. 2 is a partial cross-sectional side view of theoxygenator 200, taken along B-B depicted in FIG. 3 ; FIG. 3 is across-sectional view of a second end cap, taken along C-C, of theoxygenator 200 depicted in FIG. 2 ; and FIG. 4 is anothercross-sectional side view of the oxygenator 200, taken along A-A, shownin FIG. 3 . In embodiments, the oxygenator 200 may be, be similar to,include, or be included within the oxygenator 100 depicted in FIG. 1 .

The oxygenator 200 includes a housing 202 having a first end cap (notshown) coupled to a first end (not shown) of the housing 202 and asecond end cap 204 coupled to the second end 206 of the housing 202. Asshown, the illustrative oxygenator 200 includes a heat exchanger 208 anda gas exchanger 210. The heat exchanger 208 includes a heat-exchangercore 212 and a heat-exchanger element 214 coaxially disposed about theheat-exchanger core 212. According to various embodiments, theheat-exchanger core 212 may have any number of different types ofconfigurations and/or may include any number of features configured forimparting a desired blood flow through the oxygenator 200. For example,the heat-exchanger core 212 may include rib features, indentions, and/orthe like.

In embodiments, the heat-exchanger element 214 may include a number ofhollow fibers through which a heat-exchange fluid such as water canflow. The fibers of the heat-exchanger element 214 are bundled and thebundle is coupled, at an inlet end 216 thereof, to a heat-exchange fluidinlet channel 218, which is configured to allow an incomingheat-exchange fluid 220 to flow from a heat-exchange fluid inlet 222 tothe bundle of fibers. The blood may flow around and past the hollowfibers and thus be suitably heated. According to various embodiments,the hollow fibers may have an outer diameter of between approximately0.2 and approximately 1.0 millimeters or, more specifically, betweenapproximately 0.25 and approximately 0.5 millimeters. The hollow fibersmay be woven into mats that can range, for example, from approximately20 to approximately 200 millimeters in width. In embodiments, the matsare arranged in a criss-cross configuration. According to embodiments,the heat-exchanger element 214 may include a number of pleated thinmetal surfaces (e.g., an array of metal plates, sheets, etc.). Theheat-exchanger element 214 may include any number of other types ofheat-exchange media and/or structures.

A cylindrical shell 224 is coaxially disposed about the heat-exchangerelement 214, and the gas exchanger 210 is coaxially disposed about thecylindrical shell 224. For reference, as depicted in the figures, thecylindrical shell 224 and gas exchanger 210 may share a vertical centralaxis 215. In embodiments, the gas exchanger 210 may include a number ofmicroporous hollow gas-exchange fibers through which a gas-exchangefluid 226 (e.g., a gas such as oxygen, a mix of oxygen and one or moreother gases, air, etc.) may flow. The fibers of the gas exchanger 210are bundled and the bundle is coupled, at an inlet end (not shown)thereof to an inlet flow coupler (not shown), which is configured toprovide an incoming gas-exchange fluid 226 from a gas-exchange fluidinlet (not shown) to the bundle of fibers. Similarly, the bundle ofgas-exchange fibers may be coupled, at a gas outlet end 228 to agas-exchange fluid outlet channel 230, which is configured to providethe gas-exchange fluid 226 from the bundle to a gas-exchange fluidoutlet 232. The blood may flow around and past the hollow fibers. Due toconcentration gradients, oxygen may diffuse through the microporoushollow fibers into the blood while carbon dioxide may diffuse into thehollow fibers and out of the blood. In embodiments, the hollow fibersmay be made of polypropylene, polyester, or any other suitable polymeror plastic microporous and hydrophobic materials. According to variousembodiments, the hollow fibers have an outer diameter of approximately0.38 millimeters. According to embodiments, the microporous hollowfibers may have a diameter of between approximately 0.2 andapproximately 1.0 millimeters, or more specifically, betweenapproximately 0.25 and approximately 0.5 millimeters. The hollow fibersmay be woven into mats that can range, for example, from approximately20 to approximately 200 millimeters in width. In embodiments, the matsare arranged in a criss-cross configuration.

According to embodiments, the ends of the gas-exchange fibers and/orheat-exchange fibers or metal surfaces may be embedded within a pottingmaterial (e.g., a potting resin) 234 adjacent the end cap 204. Inembodiments, an insulating chamber 236 may be defined between a firstportion 238 of the inner surface of a flange 242 at the second end 206of the housing 202, a second portion 240 of the inner surface of theflange 242, and an inner surface 244 of the end cap 204. In embodiments,the flange 242 may be integrated with the housing 202, in which case,the flange 242 may be considered to be a part of the housing 202. Inembodiments, the flange 242 may be, for example, separately constructedand coupled to the housing.

The insulating chamber 236 may be disposed adjacent a gas outlet end246, a gas-exchange transition channel 248 of the gas exchanger 208, andthe gas-exchange fluid outlet channel 230. The insulating chamber 236may be configured to receive an insulating fluid that facilitatesmaintaining the gas-exchange fluid 226 at (or approximately) a certaintemperature or approximately within a certain temperature range. Thistemperature and/or temperature range may be selected so as to reduce theoccurrence of condensation within the gas-exchange fibers. Inembodiments, as shown, the insulating chamber 236 may include an annular(or at least partially annular) chamber, extending coaxially around atleast a portion of the gas outlet end 246 of the gas exchanger 208. Inthis case, the gas-exchange transition channel 248 may be a part of thefluid outlet channel 230.

In embodiments, the insulating chamber 236 may be designed according toany number of different shapes and to have any number of differentpositions. In embodiments, the insulating chamber 236 may be a number ofdifferent chambers (e.g., semi-annular chambers), and, in embodiments,two or more of those chambers may be connected so as to allow forinsulating fluid to move between them. In embodiments, the insulatingchamber 236 may be configured to surround a portion of the end cap 204,the entire end cap 204, a portion of the housing 202, the entire housing202, and/or the like. The insulating chamber 236 may be configured tohave a constant depth (i.e., the distance between the end of the chamber236 bounded by the inner surface 244 of the end cap 204 and the opposingportion 288 of the inner surface 240); and/or width (i.e., the distancebetween the surface 238 and the opposing portion 300 of the innersurface 240 of the flange 242). In embodiments, for example, the flange242 may include a curved configuration providing a varying volumeadjacent the housing 202.

In embodiments, the insulating fluid may be the same as theheat-exchange fluid 220, while, in other embodiments, the insulatingfluid may be a different type of fluid. In embodiments in which theinsulating fluid is different than the heat-exchange fluid, theoxygenator 200 may include an insulating fluid inlet (not shown) and/oran insulating fluid outlet (not shown), configured to facilitatecirculation of the insulating fluid into and out of the oxygenator. Inembodiments, a heating device (not shown) may be provided for modifying(e.g., increasing) the temperature of the insulating fluid before it isprovided to the oxygenator 200.

In embodiments in which the insulating fluid is the same as theheat-exchange fluid 220 of the heat exchanger 208, a first portion ofthe flow of heat-exchange fluid 220 being provided to the oxygenator 200may be provided to the heat exchanger 208, while a second portion of theheat-exchange fluid 220 being provided to the oxygenator 200 may beprovided to the insulating chamber 236. That is, for example, theheat-exchange fluid inlet channel 218 may be configured to enable afirst portion 250 of the incoming heat-exchange fluid 220 flowing fromthe heat-exchange fluid inlet 222 into the heat-exchange fluid inletchannel 218, via an aperture 252 defined in an inner wall surface 254bounding the heat-exchange fluid inlet channel 218, to flow to the heatexchanger 208, and a second portion 256 of the incoming heat-exchangefluid 220 to flow, via an aperture 258 extending from the inner wallsurface 254 bounding the heat-exchange fluid inlet channel 218 to aninner wall surface 260 bounding a first connecting channel 262, throughthe first connecting channel 262 into the insulating chamber 236. Inthis manner, a fresh supply of heat-exchange fluid 220 may becontinuously (or continually) moved through the insulating chamber 236.

A second connecting channel 264 extends from an aperture 266 defined inthe inner surface 244 of the end cap 204 to an aperture 268 defined inan inner wall surface 270 bounding a heat-exchange fluid outlet channel272. The portion 274 of heat-exchange fluid flowing into theheat-exchange fluid outlet channel 272 from the insulating chamber 236joins a portion 276 of fluid exiting the heat exchanger 208 to flow, viaan aperture 278 defined in the inner wall surface 270, to aheat-exchange outlet 282. As shown in FIG. 3 , the connecting channels262 and 264 may be arranged offset from one another as indicated bylines A-A. In other embodiments, the connecting channels 262 and 264 maybe in line with one another. The connecting channels 262 and 264 may beconfigured to have a certain size (e.g., diameter) that, coupled with acertain heat-exchange fluid flow rate into the oxygenator, imparts acertain flow rate to the portion of the heat-exchange fluid that flowsinto the insulating chamber 236. In this manner, for example, differentfluid flow rates associated with the insulating chamber 236 may beselected by substituting different end caps, each having connectingchannels, inlet channels, and/or outlet channels sized to impartcorresponding flow rates, thus influencing the blood/gas temperaturegradient.

As shown in FIGS. 2-4 , the insulating chamber 236 surrounds the gasoutlet end 246 of the gas exchanger 210, as well as the gas-exchangefluid outlet channel 230 and the gas-exchange transition channel 248. Asis illustrated, the insulating chamber 236; the channels 218, 230, 272,248; and the connecting channels 262 and 264 may be defined in an innersurface 286 of the end cap 204. For example, in embodiments, the end capmay be manufactured to include any one or more of the features 218, 230,236, 262, 264, 272, and 248. In other embodiments, one or more of theinsulating chamber 236; the channels 218, 230, 272, 248; and theconnecting channels 262 and 264 may be defined within one or moreportions of the housing 202, defined by a combination of one or moreportions of the housing 202 and one or more portions of the innersurface 286 of the end cap 204, defined within an insert (like theflange 242) configured to be disposed between the end cap 204 and thehousing 202 (and/or the heat exchanger 208, the gas exchanger, etc.),and/or the like.

The illustrative oxygenator 200 shown in FIGS. 2-4 is not intended tosuggest any limitation as to the scope of use or functionality ofembodiments of the present disclosure. The illustrative oxygenator 200should not be interpreted as having any dependency or requirementrelated to any single component or combination of components illustratedtherein. Additionally, various components depicted in FIGS. 2-4 may be,in embodiments, integrated with various ones of the other componentsdepicted therein (and/or components not illustrated), all of which areconsidered to be within the ambit of the present disclosure.

As explained above, embodiments may include an oxygenator having aninsulating chamber disposed around at least a portion of the housing ofthe oxygenator. This may be particularly true, e.g., in the case ofsmall CPB or ECMO oxygenators. FIG. 5 is a schematic depiction of anillustrative oxygenator having an insulating chamber, in accordance withembodiments of the disclosed subject matter.

FIG. 5 depicts an illustrative oxygenator 500 configured to be used insmall CPB operations, in accordance with embodiments of the disclosedsubject matter. According to embodiments, the oxygenator 500 may be, besimilar to, include, be included in, or include similar features as theoxygenator 100 depicted in FIG. 1 and/or the oxygenator 200 depicted inFIGS. 2-4 . As shown, the oxygenator 500 includes a housing 502, a firstend cap 504 disposed at a first end 506 of the housing, and a second endcap 508 disposed at a second end 510 of the housing 502. An insulatingchamber 512 is disposed around at least a portion of the housing 502. Inembodiments, that is, the insulating chamber 512 may be coupled to anouter surface of the housing 502, while, in other embodiments, theinsulating chamber 512 may be defined within the housing, e.g., justunder the outer surface thereof. As illustrated, the insulating chamber512 extends from the first end 506 of the housing 502 to the second end510 of the housing 502. In other embodiments, the insulating chamber 512only extends part of the way between the first and second ends 506 and510 of the housing 502. Similarly, in embodiments, the insulatingchamber 512 may be disposed circumferentially around (inside the housing502 or outside the housing 502) the entire circumference of the housing502, or may extend only partially around (inside the housing 502 oroutside the housing 502) the circumference of the housing 502.

As shown in FIG. 5 , the insulating chamber 512 includes aninsulating-fluid inlet 514 configured to provide insulating fluid froman insulating-fluid source (e.g., a fluid heating device, a reservoir ora container, a heat exchanger, etc.), to the insulating chamber 512. Theinsulating chamber 512 also includes an insulating-fluid outlet 516configured to facilitate removing insulating fluid from the insulatingchamber 512. In embodiments, the insulating-fluid inlet 514 may becoupled to a heat-exchange fluid inlet 518 via a conduit 520 disposedwithin the oxygenator 500 and/or outside of the oxygenator 500. Inembodiments, for example, a first inlet conduit (not shown) may extendfrom the heat-exchange fluid inlet 518 to a heat exchanger (not shown)disposed within the housing 502, and a second inlet conduit (not shown,but indicated conceptually at 520) may extend from the heat-exchangefluid inlet 518, or from the first inlet conduit, to theinsulating-fluid inlet 514, which may be defined within the housing 502and/or on the outside of the housing 502. Similarly, a first outletconduit (not shown) may extend from the heat exchanger to aheat-exchange fluid outlet 522, and a second outlet conduit (not shown,but indicated conceptually at 524) may extend from the insulting-fluidoutlet 516 (which may be disposed within the housing 502 and/or outsideof the housing 502) to the heat-exchange fluid outlet 522, or to thefirst outlet conduit.

The illustrative oxygenator 500 shown in FIG. 5 is not intended tosuggest any limitation as to the scope of use or functionality ofembodiments of the present disclosure. The illustrative oxygenator 500should not be interpreted as having any dependency or requirementrelated to any single component or combination of components illustratedtherein. Additionally, various components depicted in FIG. 5 may be, inembodiments, integrated with various ones of the other componentsdepicted therein (and/or components not illustrated), all of which areconsidered to be within the ambit of the present disclosure.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentdisclosure. For example, while the embodiments described above refer toparticular features, the scope of this disclosure also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present disclosure is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

We claim:
 1. An oxygenator configured to oxygenate blood flowingtherethrough, the oxygenator comprising: a housing having a blood inletand a blood outlet, the blood inlet and the blood outlet in fluidcommunication with an interior of the housing; a heat exchanger disposedwithin the housing, the heat exchanger including a heat-exchange fluidinlet, a heat-exchange fluid outlet, and a bundle of gas-exchange fibersthrough which a heat-exchange fluid is configured to flow from a fluidinlet end of the bundle of heat-exchange fibers to a fluid outlet end ofthe bundle of heat-exchange fibers; a gas exchanger disposed within thehousing, the gas exchanger including a gas-exchange fluid inlet, agas-exchange fluid outlet, and a bundle of gas-exchange fibers throughwhich a gas-exchange fluid is configured to flow from a gas inlet end ofthe bundle of gas-exchange fibers to a gas outlet end of the bundle ofgas-exchange fibers; and an insulating chamber configured to receive aninsulating fluid to thermally insulate at least the gas outlet end ofthe bundle of gas-exchange fibers proximate the gas-exchange fluidoutlet.
 2. The oxygenator of claim 1, wherein the insulating fluidfacilitates maintaining the gas-exchange fluid at a certain temperatureor within a certain temperature range.
 3. The oxygenator of claim 1,wherein the oxygenator includes an insulating fluid inlet and aninsulating fluid outlet configured to facilitate circulation of theinsulating fluid through the insulating chamber.
 4. The oxygenator ofclaim 3, wherein the insulting chamber is configured to receive aportion of the heat-exchange fluid from the heat exchanger as theinsulating fluid.
 5. The oxygenator of claim 1, wherein the insulatingfluid is a fluid other than blood flowing through the oxygenator.
 6. Theoxygenator of claim 1, wherein ends of the heat-exchange fibers areembedded in a potting material.
 7. The oxygenator of claim 1, whereinends of the gas-exchange fibers are embedded in a potting material. 8.The oxygenator of claim 7, wherein at least a portion of the insulatingchamber is disposed radially outward of the potting material upstream ofthe gas outlet end of the gas-exchange fibers.
 9. The oxygenator ofclaim 1, wherein the heat-exchange fibers are woven into mats arrangedin a criss-cross configuration.
 10. The oxygenator of claim 1, whereinthe gas-exchange fibers are woven into mats arranged in a criss-crossconfiguration.
 11. The oxygenator of claim 1, further comprising aconduit disposed outside of the housing and configured to provide theinsulating fluid to the insulating chamber.
 12. An oxygenator configuredto oxygenate blood flowing therethrough, the oxygenator comprising: ahousing having a blood inlet and a blood outlet, the blood inlet and theblood outlet in fluid communication with an interior of the housing; aheat exchanger disposed within the housing, the heat exchanger includinga heat-exchange fluid inlet, a heat-exchange fluid outlet, and a bundleof gas-exchange fibers through which a heat-exchange fluid is configuredto flow from a fluid inlet end of the bundle of heat-exchange fibers toa fluid outlet end of the bundle of heat-exchange fibers; a gasexchanger disposed within the housing, the gas exchanger including agas-exchange fluid inlet, a gas-exchange fluid outlet, and a bundle ofgas-exchange fibers through which a gas-exchange fluid is configured toflow from a gas inlet end of the bundle of gas-exchange fibers to a gasoutlet end of the bundle of gas-exchange fibers; and an insulatingchamber configured to receive an insulating fluid therein, the chamberin fluid communication with an insulating fluid inlet and an insulatingfluid outlet, such that the insulating fluid is configured to flowthrough the insulating chamber from the insulating fluid inlet to theinsulating fluid outlet.
 13. The oxygenator of claim 12, wherein theinsulating fluid facilitates maintaining the gas-exchange fluid at acertain temperature or within a certain temperature range.
 14. Theoxygenator of claim 12, wherein the insulting chamber is configured toreceive a portion of the heat-exchange fluid from the heat exchanger asthe insulating fluid.
 15. The oxygenator of claim 12, wherein theinsulating fluid is a fluid other than blood flowing through theoxygenator.
 16. The oxygenator of claim 12, wherein ends of theheat-exchange fibers are embedded in a potting material.
 17. Theoxygenator of claim 12, wherein ends of the gas-exchange fibers areembedded in a potting material.
 18. The oxygenator of claim 17, whereinat least a portion of the insulating chamber is disposed radiallyoutward of the potting material upstream of the gas outlet end of thegas-exchange fibers.
 19. The oxygenator of claim 12, wherein theheat-exchange fibers are woven into mats arranged in a criss-crossconfiguration.
 20. The oxygenator of claim 12, wherein the gas-exchangefibers are woven into mats arranged in a criss-cross configuration.